Eesti normides jaotatakse materjalid süttivuse seisukohalt põlevateks ja mittepõlevateks . materjalid liigitatakse 3 kategooriasse: 1. Mittepõlevad - ei sütti, ei põle, ei söestu ega hõõgu iseseisvalt 2. Raskelt põlevad, 3. Põlevad (combustible) on kõik orgaanilised materjalid kui nad pole immutatud 1.5.3.17.Termiline püsivus. Materjali võimet purunemata taluda vahelduvaid temperatuurimuutusi nimetatakse termiliseks püsivuseks. 1.5.3.18.Mahupüsivus Soundness Mahupüsivus on materjali omadus säilitada peale valmistamist ekspluatatsiooni tingimustes oma geomeetriline kuju ja ruumala ning mitte praguneda tema sees toimuvate reaktsioonide või pingete tõttu Mahumuutusi põhjustavad: · temperatuuri muutumine · niiskuse muutumine · ja ka materjalis toimuvad füüsikalis-keemilised protsessid 1.5.3.19.Peenus (disperssus) Fineness. Pulbrilise materjali peenust iseloomustatakse tema terade hulkade jaotumisega terasuuruste järgi 1.5.3.19.1
Validity To overcome the ambiguities of the commonsense notion of ‘following from’, we introduce the technical notion of validity. Question: 1. ‘Does the conclusion follow from the premises?’ can be rephrased as: 1. Is the argument valid? An argument is valid if it is impossible for its premise(s) to be (all of them) true and its conditions false. In a valid argument, if the premises are all true, then the conclusion is necessarily true. Soundness An argument might be valid even when some or all its premises are false and/or its conclusion is false. No Human is mortal Aristotle is a human Therefore, Aristotle is not mortal. The validity of an argument does not guarantee the truth of its conclusion. An argument is Sound if it is valid and has (all non-superflous) true premises. Sound = Valid + (all) true premises It is important to remember the difference between valid and sound argument.
He seeks to get out his solutions as quickly as possible. It is probably true that a message will always have some historical value, but that is small comfort to a commander who does not get a cryptanalysis that would have warned him of an enemy attack until after the attack is under way. The factors that affect the time required to solve cryptograms—aside from external factors, like the speed of sending the intercepts back to the cryptanalyst— are the strength of the system, the soundness of the regulations for its use, how closely the cipher clerks follow those regulations, the volume of text, the size and skill of the cryptanalytic organization, and the amount and character of collateral information. Bringing skill into the picture raises the question of whether cryptanalysis is a science or an art. It is both. On the one hand, cryptanalysis—or, more properly in this context, cryptanalytics—is an organized body of knowledge. It studies and controls phenomena. Its
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